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Message-ID: <20231030124041.GE691768@ziepe.ca>
Date: Mon, 30 Oct 2023 09:40:41 -0300
From: Jason Gunthorpe <jgg@...pe.ca>
To: "Zhijian Li (Fujitsu)" <lizhijian@...itsu.com>
Cc: "zyjzyj2000@...il.com" <zyjzyj2000@...il.com>,
"leon@...nel.org" <leon@...nel.org>,
"linux-rdma@...r.kernel.org" <linux-rdma@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"rpearsonhpe@...il.com" <rpearsonhpe@...il.com>,
"Daisuke Matsuda (Fujitsu)" <matsuda-daisuke@...itsu.com>,
"bvanassche@....org" <bvanassche@....org>
Subject: Re: [PATCH RFC 1/2] RDMA/rxe: don't allow registering !PAGE_SIZE mr
On Mon, Oct 30, 2023 at 07:51:41AM +0000, Zhijian Li (Fujitsu) wrote:
>
>
> On 27/10/2023 13:41, Li Zhijian wrote:
> > mr->page_list only encodes *page without page offset, when
> > page_size != PAGE_SIZE, we cannot restore the address with a wrong
> > page_offset.
> >
> > Note that this patch will break some ULPs that try to register 4K
> > MR when PAGE_SIZE is not 4K.
> > SRP and nvme over RXE is known to be impacted.
> >
> > Signed-off-by: Li Zhijian <lizhijian@...itsu.com>
> > ---
> > drivers/infiniband/sw/rxe/rxe_mr.c | 6 ++++++
> > 1 file changed, 6 insertions(+)
> >
> > diff --git a/drivers/infiniband/sw/rxe/rxe_mr.c b/drivers/infiniband/sw/rxe/rxe_mr.c
> > index f54042e9aeb2..61a136ea1d91 100644
> > --- a/drivers/infiniband/sw/rxe/rxe_mr.c
> > +++ b/drivers/infiniband/sw/rxe/rxe_mr.c
> > @@ -234,6 +234,12 @@ int rxe_map_mr_sg(struct ib_mr *ibmr, struct scatterlist *sgl,
> > struct rxe_mr *mr = to_rmr(ibmr);
> > unsigned int page_size = mr_page_size(mr);
> >
> > + if (page_size != PAGE_SIZE) {
>
> It seems this condition is too strict, it should be:
> if (!IS_ALIGNED(page_size, PAGE_SIZE))
>
> So that, page_size with (N * PAGE_SIZE) can work as previously.
> Because the offset(mr.iova & page_mask) will get lost only when !IS_ALIGNED(page_size, PAGE_SIZE)
That makes sense
Jason
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